Brown widow spiders

What they do: The females are ½-inch-long arachnids that carry fangs long enough to break the skin and inject neurotoxin that, while rarely causing death, can be quite painful. Generally shy, they may become aggressive to protect egg sacs or when trapped in a person’s clothing.

Where they live: String webs in dark areas like under desks or in ventilation ducts or undisturbed nooks and crannies outdoors.

Navy rap sheet: Brown widows boarded the Military Sealift Command cargo ship Benavidez in late 2012, dropping “egg sacs” and laying webs on the weather deck, main deck and well deck loading doors — alarming crew members, according to a site visit report.

How to prevent: Routinely clean outdoor areas of debris and sweep around piping and storage areas, to prevent spiders from laying webs and then getting indoors.

How to destroy: Insecticides and vacuuming up crevices where they lurk. In some cases, efforts may only force the spiders farther into a crack or crevice.

Bedbugs

What they do: These red, ¼-inch-long crawlers feast primarily on human blood while their victims sleep. Feedings can stretch from three to 15 minutes and often leave a trail of red bite marks behind.

Where they live: Bedbugs typically arrive with boxes, luggage or laundry and hide in mattress folds and bedding, ready to ambush sleepers.

How to prevent: Make sure bats and birds don’t live in a berthing area or barracks, monitor your luggage closely and inspect a used mattress closely before sleeping on it.

How to destroy: Wash affected bedding and dispose of the mattress. Insecticides can be used on carpets but are less useful on mattresses, where bugs can find other crevices and which can often make the material toxic to humans, too. “Control of bedbugs on mattresses is difficult to achieve,” the Aug. 5 report states.

West Indian drywood termites

What they do: A colony of these ½-inch-long blind termites can bore through wood structures and furniture and render them unsound while still concealed within the wood.

Where they live: Tropical climates like Hawaii and the southeastern U.S. They attack lumber and structural frames of both hard and soft woods.

Navy rap sheet: Termite-infested maple was inadvertently installed on the attack submarine Albuquerque in the sub’s battery well and was removed after a crew member suspected an infestation in April 2010. Noting their resilience, an inspector wrote that these termites could “become an established infestation in the battery well.”

How to prevent: Inspect wood for cracks and holes of the kind termites leave when boring in, as well as sawdust piles. Also check for signs of shed wings or small droppings, known as “frass.”

How to destroy: Remove all wood suspected of contamination. One effective extermination method is drilling into the colony and injecting insecticide.

Sawtoothed grain beetles

What they do: These rust-colored, 1⁄8-inch-long beetles feast on dry goods, including rice, flour, pancake mix and pasta, jerky, powdered milk — even chocolate. Their sawtoothed appendages can pierce cardboard, plastic and cellophane.

Where they live: Inside food packages.

Navy rap sheet: A colony of sawtoothed beetle stowaways on the frigate Gary lived in a rice bag and was spotted in April. An inspector called them the “most common, nonmedically important, stored product pest found aboard ships.”

How to prevent: Inspect dry goods for beetles and signs of small holes they leave when chewing into packages.

How to destroy: Dispose of infested goods.

Mosquitoes

What they do: Female mosquitoes pierce the skin of their prey with bladed mandibles and then suck blood, which provides the nutrients for their eggs. They can transmit diseases between their victims and are known for spreading illnesses such as malaria, West Nile virus and dengue.

Where they live: Regions with stagnant water. Uncommon aboard ship but are a threat to sailors on expeditionary bases, especially in tropical regions.

Navy rap sheet: Mosquitoes harried sailors and their families at Pearl City Peninsula military housing in Hawaii in 2010. The mosquitoes thrived in an adjacent mangrove swamp. “Long-term mosquito management issue,” an inspector noted.

How to prevent: Seal all sleeping and living areas. Remove stagnant water from areas near the base. Wear long-sleeved uniforms around dusk, when mosquitoes are most active, and spray on insect repellent. Take prescribed anti-malaria drugs before traveling to an at-risk region.

How to destroy: Aerosol insecticides and removing standing water.

German cockroaches

What they do: The most common shipboard pest, these ½-inch-long scavengers can transmit diseases such as dysentery, food poisoning and diarrhea. They also release a foul odor on the food they contaminate.

Where they live: These flat crawlers thrive in galleys and spaces with standing water and exposed food. They are mostly nocturnal munchers whose favorite snacks include sweets, grease, meat and starches.

Navy rap sheet: Cockroaches overran the frigate John L. Hall’s galley, scullery, chiefs’ mess and wardroom. Inspectors said the primary culprit was unsanitary conditions on the ship. Traps caught 559 roaches after the first week they were laid, in late December 2009. Multiple visits and training were required to oust the infestation.

How to prevent: Inspect all stores coming aboard and keep galleys squeaky clean.

How to destroy: Sticky traps and flushing pesticides.

Roof rats

What they do: These rodents spread the bubonic plague, which wiped out a third of Europe’s population in the 14th century. They still can transmit this disease and many others, such as murine typhus, 7-day fever and foodborne illnesses. Mice are another rodent species that carries similar diseases and has roosted aboard ships.

Where they live: They are also known as “ship rats” for their ability to thrive aboard ship and are “excellent climbers” who can chew on wiring insulation, in addition to their regular diet of seeds and fruit, according to the Navy’s Shipboard Pest Control Manual. Including tail, they can grow up to 18 inches long.

Navy rap sheet: A colony of roof rats settled in the dry provisions storeroom of the attack submarine La Jolla in 2008. “The rodents were traveling throughout the vessel via the outboard” and also had come to nest in the torpedo room, an inspector noted. The ship caught 86 rats following an inspector’s visit, and the rats still persisted seven months later. “Some rodents have become familiar with the mechanical spring traps,” the inspector wrote, recording that one even appeared to have removed a trap’s spring. They were “very well-established” aboard the sub, the inspector noted.

How to prevent: Proper sanitation and rat guards on all mooring lines to prevent them from climbing aboard.

How to destroy: Rat traps. La Jolla’s crew found that wary rats could be enticed into the traps with peanut butter.

Flies

What they do: Flies feed on fruit, rotting food and even feces and can spread sickening bacteria.

Where they live: Anywhere they can feast on food or garbage. Typical spots include galleys and berthing — even by the vending machines when there is a sugar residue from spills.

Navy rap sheet: Phorid flies, which feed on human waste, infested the heads on the attack submarine Cheyenne in late 2011 and deposited their larvae on a sanitary tank. It took weeks and multiple visits for exterminators to rid the sanitary tank and associated plumbing of flies.

How to prevent: Keep spaces clean and dispose of rotting food quickly.

How to destroy: Seal crevices were they reside and spray infested spaces with insecticide.

SOURCES: NAVY BUREAU OF MEDICINE AND SURGERY, ARMY PUBLIC HEALTH COMMAND